1. Field of the Invention
The present invention generally relates to diaper construction and, more particularly, is concerned with a diaper having a centrally-located layer of a fluid-permeable chromatographic medium with a peripherally-located wetness indicator.
2. Description of the Prior Art
A diaper is used on small children, infants and toddlers, to capture fluid and solid waste. When the diaper is wet or otherwise soiled from such waste, it is desirable and usually necessary to replace the diaper as soon as possible. A problem exists, however, in that it can be difficult to determine by touch whether a diaper on a child is wet or not because diapers generally have more than one layer and the outer layer is typically impermeable to the waste.
In order to provide a solution for this problem, wetness indicators for diapers have been developed over the years. Representative examples of prior art diaper wetness indicators are the ones disclosed in U.S. Pat. No. 3,731,685 to Eidus and U.S. Pat. No. 5,947,943 to Lee. In the Eidus patent, a diaper moisture indicating strip is disclosed for use in connection with a cloth diaper. One end of the Eidus diaper moisture indicating strip is attached to the cloth diaper near the periphery of the diaper and the other free end of the strip has a chemical which changes color when wet. The Eidus strip operates by capillary action. The Eidus strip, however, is dependent upon being attached at a substantially peripheral location on the diaper where fluid, such as urine, will not immediately directly contact the innermost end of the strip and thus the fluid will be delayed in reaching the moisture-indicating chemical on the outer end of the strip.
In the Lee patent, a wetness-indicating material is disposed on an interior-facing side of a back sheet of a diaper. The Lee wetness-indicating material changes its appearance after it is exposed to water. The Lee patent, however, appears to be unduly complex and costly for achieving this objective.
Consequently, a need still exists for an innovation in diaper construction which will provides an optimum solution for the problem of indicating wetness without introducing any new problems in place thereof.
The present invention provides a diaper which satisfies the aforementioned need. The diaper includes a layer of a fluid-permeable chromatographic medium which has a centrally-located portion and a peripherally-located wetness indicator. The layer is relatively simple and cost-effective in its construction. The diaper with such a layer operates in a comprehensive fashion in that it will respond to the presence of fluid at the centrally-located region of the diaper where fluid always makes its initial contact with the diaper.
Accordingly, the present invention is directed to a diaper which comprises: (a) a diaper substrate having a peripheral edge and a centrally-located region where fluid from a user will make initial contact therewith; (b) a fluid transport layer disposed within the diaper substrate and having a peripheral edge and a centrally-located portion disposed at the centrally-located region of the diaper substrate; and (c) a wetness indicator on the peripheral edge of the transport layer and exposed and extending along at least a portion of the peripheral edge of the diaper substrate; (d) the fluid transport layer being made of a fluid-permeable chromatographic medium capable of drawing fluid via capillary action from the centrally-located portion of the layer at the centrally-located region of the diaper substrate toward the peripheral edge of the layer and into contact with the wetness indicator, the wetness indicator being a material capable of eliciting a visible response in the presence of fluid.
These and other features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there is shown and described an illustrative embodiment of the invention.